The invention relates to a support device for semi-trailers comprising a leg which has a receiving device, on its lower end. The support leg has a base element with a base plate, which is mounted by means of two vertical plates on the base receiving device so that it can move vertically and can pivot. Between the base plate and the base receiving device there is a damping element. To achieve an improved pivoting capability of the support base, whereby the damping element is subjected to a small deformation, the damping element is located on the underside of the base receiving device so that cannot pivot, and is supported on a curved plate which is fixed to the base plate and the contour of which is adapted to the pivoting movement of the base plate in relation to the supporting leg.